Directional drilling of a subsurface formation may be advantageous for any of several reasons. By way of example, directional drilling can increase the length of the wellbore through a reservoir that is to be produced. Also, directional drilling can permit access to reservoirs where vertical access is difficult or not possible. Directional drilling may allow more wellheads to be grouped together at a surface location, thereby reducing surface area disturbance and reducing rig moves.
A directional drilling path is often predetermined before drilling commences, and a downhole instrument may be utilized to provide the inclination and azimuth of the wellbore during the drilling process. This is particularly true of measurement while drilling (MWD) tools that provide “real-time” feedback during drilling.
Presently, there are various directional drilling systems available. Most common are “rotary steerable systems” or “RSS.” The assignee hereof provides various options in an RSS, including the PowerDrive, PowerDrive Xceed, PowerDrive Archer and PowerDrive Vortex systems.